Revision 321027c1fe77f892f4ea07846aeae08cefbbb290 authored by Peter Zijlstra on 11 January 2017, 20:09:50 UTC, committed by Ingo Molnar on 14 January 2017, 09:56:11 UTC
Di Shen reported a race between two concurrent sys_perf_event_open()
calls where both try and move the same pre-existing software group
into a hardware context.
The problem is exactly that described in commit:
f63a8daa5812 ("perf: Fix event->ctx locking")
... where, while we wait for a ctx->mutex acquisition, the event->ctx
relation can have changed under us.
That very same commit failed to recognise sys_perf_event_context() as an
external access vector to the events and thereby didn't apply the
established locking rules correctly.
So while one sys_perf_event_open() call is stuck waiting on
mutex_lock_double(), the other (which owns said locks) moves the group
about. So by the time the former sys_perf_event_open() acquires the
locks, the context we've acquired is stale (and possibly dead).
Apply the established locking rules as per perf_event_ctx_lock_nested()
to the mutex_lock_double() for the 'move_group' case. This obviously means
we need to validate state after we acquire the locks.
Reported-by: Di Shen (Keen Lab)
Tested-by: John Dias <joaodias@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Min Chong <mchong@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: f63a8daa5812 ("perf: Fix event->ctx locking")
Link: http://lkml.kernel.org/r/20170106131444.GZ3174@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent 63cae12
hash_info.c
/*
* Hash Info: Hash algorithms information
*
* Copyright (c) 2013 Dmitry Kasatkin <d.kasatkin@samsung.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <linux/export.h>
#include <crypto/hash_info.h>
const char *const hash_algo_name[HASH_ALGO__LAST] = {
[HASH_ALGO_MD4] = "md4",
[HASH_ALGO_MD5] = "md5",
[HASH_ALGO_SHA1] = "sha1",
[HASH_ALGO_RIPE_MD_160] = "rmd160",
[HASH_ALGO_SHA256] = "sha256",
[HASH_ALGO_SHA384] = "sha384",
[HASH_ALGO_SHA512] = "sha512",
[HASH_ALGO_SHA224] = "sha224",
[HASH_ALGO_RIPE_MD_128] = "rmd128",
[HASH_ALGO_RIPE_MD_256] = "rmd256",
[HASH_ALGO_RIPE_MD_320] = "rmd320",
[HASH_ALGO_WP_256] = "wp256",
[HASH_ALGO_WP_384] = "wp384",
[HASH_ALGO_WP_512] = "wp512",
[HASH_ALGO_TGR_128] = "tgr128",
[HASH_ALGO_TGR_160] = "tgr160",
[HASH_ALGO_TGR_192] = "tgr192",
[HASH_ALGO_SM3_256] = "sm3-256",
};
EXPORT_SYMBOL_GPL(hash_algo_name);
const int hash_digest_size[HASH_ALGO__LAST] = {
[HASH_ALGO_MD4] = MD5_DIGEST_SIZE,
[HASH_ALGO_MD5] = MD5_DIGEST_SIZE,
[HASH_ALGO_SHA1] = SHA1_DIGEST_SIZE,
[HASH_ALGO_RIPE_MD_160] = RMD160_DIGEST_SIZE,
[HASH_ALGO_SHA256] = SHA256_DIGEST_SIZE,
[HASH_ALGO_SHA384] = SHA384_DIGEST_SIZE,
[HASH_ALGO_SHA512] = SHA512_DIGEST_SIZE,
[HASH_ALGO_SHA224] = SHA224_DIGEST_SIZE,
[HASH_ALGO_RIPE_MD_128] = RMD128_DIGEST_SIZE,
[HASH_ALGO_RIPE_MD_256] = RMD256_DIGEST_SIZE,
[HASH_ALGO_RIPE_MD_320] = RMD320_DIGEST_SIZE,
[HASH_ALGO_WP_256] = WP256_DIGEST_SIZE,
[HASH_ALGO_WP_384] = WP384_DIGEST_SIZE,
[HASH_ALGO_WP_512] = WP512_DIGEST_SIZE,
[HASH_ALGO_TGR_128] = TGR128_DIGEST_SIZE,
[HASH_ALGO_TGR_160] = TGR160_DIGEST_SIZE,
[HASH_ALGO_TGR_192] = TGR192_DIGEST_SIZE,
[HASH_ALGO_SM3_256] = SM3256_DIGEST_SIZE,
};
EXPORT_SYMBOL_GPL(hash_digest_size);
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